Slicing machine feeding device

ABSTRACT

A slicing machine includes a rotatable blade (1) and a feeding device (4, 5) for feeding blocks of product (46) towards the blade (1). The feeding device comprises opposed driven endless track assemblies (4, 5) having their adjacent faces arranged to be driven in the same direction. One of the opposed track assemblies (4) is formed by a number of separate side-by-side endless tracks (6, 7, 8, 9) which are pivotally connected to a common support (20). The number of separate tracks (6, 7, 8, 9) have a ganged drive and pneumatic rams (22) which, in use, urge the downstream ends of the tracks independently towards the block of product (46) so that the separate tracks pivot independently and hold a block of product (46) the thickness of which is not uniform in the transverse direction. The support (20) supports the upstream ends of the endless tracks (6, 7, 8, 9) and is slideably mounted for movement in a direction parallel to the plane of the blade (1). A pneumatic actuator (21) is provided to urge the support (20) towards the other endless track assembly (5) to accommodate differences in thickness between subsequent blocks of product (46).

BACKGROUND OF THE INVENTION

Slicing machines are used for slicing blocks of meat, meat products andother food products such as cheese. Typically they include a rotatingblade having a spiral cutting edge, or a rotating blade having acircular cutting edge which is mounted for orbital motion so that uponeach rotation of the spiral cutting edge blade or each orbit of thecircular cutting edge blade its cutting edge moves across the face of ablock of product to cut a slice from it. The block of product is fedstepwise and moves when the cutting edge is out of contact with it or isfed forwards continuously so that the cutting edge follows a generallyhelical path through the block. Conventionally the block of productrests on a stationary bed and is driven forwards towards the blade by apusher having a gripper or suction pad which engages the rear face ofthe block of product. In this case a spring loaded paddle usually bearsdownwards on the block of product to steady it towards its downstreamend.

It is also known to replace the stationary bed and pusher by a pair ofopposed driven conveyors having their adjacent faces arranged to bedriven in the same direction. An example of a slicing machine with sucha feeding device is shown in U.S. Pat. No. 3,162,226 which has the pairof opposed conveyors mounted above and below the block of product. Thespacing between the opposed conveyors is manually adjustable and theupper conveyor is mounted at about its mid-point by a spring loadedconnection which can accommodate small variations in the height ofblocks of product. Such arrangements are particualrly useful becausethey enable blocks of product to be fed successively so that they can besliced with substantially no interruption between them and they avoidthe need for interrupting the slicing whilst the pusher is withdrawn anda further block is located on the stationary bed.

One problem however with this type of arrangement is that although thedownstream end of the conveyors approach the plane of cut of the bladebecause of the curvature of the end rollers of the conveyor the last 30to 40 mms of each block is substantially unsupported. As this portion iscut by the blade the blade tends to grab the block and pull it too fardownstream so cutting slices that are thicker than required. Thisproblem is exaggerated still further in the arrangement shown in U.S.Pat. No. 3,162,226 because of the way in which the upper conveyor isconnected at about its mid-point by a spring loaded connection. Thisresults in the end portions of each block being inadequately held. In anattempt to overcome this U.S. Pat. No. 3,162,226 includes an additionalplate which engages the cut face of the block of product and supportsthe cut face in position as the blade moves towards it. This additionalplate oscillates back and forth with the cutting edge of the blade.

It is known that the quality of slices cut by a slicing machine is verydependent upon the support and control of the movement of the block ofproduct and particularly the support and control of the movement of theend portion of the block of product. Many other attempts have been madeto support the product as firmly as possible and as close as possible tothe plane of cut of the blade. Meat and similar food products areflexible and somewhat fragile. If they are not held firmly enough theblock tends to be pulled as the blade is cutting a slice from its faceas has already been mentioned. This problem is particularly bad forblocks having non-parallel sides. Meat such as sides of bacon are anatural product and even after they have been subjected to a pressingoperation their sides are not flat and certainly not parallel. Moldedproducts such as molded meat products and cheese often have sides whichare flat but are not parallel to one another since the mold includes ataper to enable the product to be de-molded. Thus even if opposite sidefaces of such molded products are flat they are often not parallel.

A significant attempt to overcome all of these problems is disclosed inGB-A-2133279 which discloses a slicing machine including a rotatableblade and a feeding device for feeding blocks of product towards theblade, the feeding device being divided in a direction transverse to itsfeed direction into a number of separate elements pivotally connected toa common support and having a ganged drive and biasing means which, inuse, urge the separate elements adjacent the blade independently towardsthe block of product so that the separate elements pivot independentlyand hold a block of product the thickness of which is not uniform in thetransverse direction. In this example the separate elements are formedby rollers which engage only the downstream end of the block of productwhich include backwardly facing teeth to resist the forwards pull of theknife-blade. The rollers are supported by a pivoted parallelogram-typelinkage but, nevertheless, as the rollers pivot and move towards theblock of product they tend to move further away from the plane of cut ofthe blade and so support the product less effectively.

This British specification is a further improvement over an earlierattempt to hold securely the last portion of a block of product which isdescribed in U.S. Pat. No. 4,329,900. In this earlier specification onlya single roller is pivotally mounted and arranged to bear against thedownstream end of a block of product. Since the arrangement shown inthis earlier specification only uses a simple pivot rather than aparallelogram linkage the roller tends to move even further away fromthe plane of cut of the blade as it pivots towards the block of product.

The feeding device disclosed in these two specifications undoubtedlysupports the end portions of each block of product more firmly and asclose as possible to the plane of cut of the blade than the conventionalarrangement such as that disclosed in U.S. Pat. No. 3,162,226. However,they both tend only to engage the product to both feed it and preventthe forward pull from the blade along a single line of contact which,particularly with delicate products leads to damage of the product.

SUMMARY OF THE INVENTION

According to this invention a slicing machine such as disclosed inGB-A-2133279, is characterised in that the feeding device comprisesopposed driven endless track assemblies having their adjacent facesarranged to be driven in the same direction, one of the opposed trackassemblies being formed by a number of separate side-by-side endlesstracks, in that the support supports the upstream end of the endlesstracks and is slideably mounted for movement in a direction parallel tothe plane of the blade, and in that a pneumatic actuator is provided tourge the support towards the other endless track assembly.

By replacing the toothed roller assembly described in GB-A-2133279 withopposed track assemblies a very much better control of the feed of theblock of product is obtained. The tracks spread the gripping load over avery much larger area which prevents a feeding device damaging theproduct and as a result of it being positively fed on both sides by theopposed tracks the feed of the block of product is also spread over agreater area of product. However, more importantly, because the supportfor the number of separate tracks is slideably mounted and biasedtowards the other of the opposed tracks the downstream ends of theseparate tracks move strictly parallel to the plane of the blade. Thus,as the support moves to accommodate different thicknesses of block thedownstream end of the separate tracks remain at a substantially constantdistance from the plane of cut of the blade and do not move away fromthe blade as the thickness of the block decreases as does thearrangement shown in GB-A-2133279 and U.S. Pat. No. 4,329,900. It isonly the movement of the downstream ends of the pivoted tracks resultingfrom differences in thickness of the block of product in the transversedirection which results in any pivoting movement of the separate tracksand this is very small compared to the differences in thickness ofdifferent blocks. The pneumatic actuator provides a controlled andconstant pressure on the support and hence on the separate tracksirrespective of its displacement.

Preferably the tracks have the smallest practical diameter at theirdownstream end but, even then with their downstream end close to theplane of the blade the final portion of the block equivalent to theradius of the downstream end of the endless tracks is unsupported.Preferably therefore elongate guide fingers are intercallated betweenthe independent tracks and are arranged to engage and support theproduct immediately adjacent the blade and so support the product rightup to its downstream end. The fingers may be independently biaseddownwards onto the surface of the block of product but preferably theyare connected to a support for an adjacent track and move towards andaway from the opposite track assembly with that track. Typically thesupport fingers extend to within 1 or 2 mm of the plane of cut of theblade.

Preferably the separate tracks include a support arranged towards theirdownstream end to bear against the tracks and urge them towards theother track assembly. The support may be spring loaded to encourage thetracks to conform to the surface of the block or product over asubstantial proportion of its length.

The tracks may be formed by a continuous belt having a plain or ribbedsurface but preferably they are formed by sprocket chain havingtransverse plates attached to adjacent links. The transverse plates mayinclude spikes or other projections arranged positively to engage theblock of product but we have found that plates having a stepped surfaceare particularly effective in supporting and holding the product firmlywithout damaging it.

The opposite track assembly may also be formed by a number of parallelside-by-side tracks arranged independently but, it is normallysufficient for the other track assembly to be formed by a singleconveying track assembly. Most products include at least one face whichis substantially planar and thus, by placing this substantially planarface onto the other track assembly the track assembly formed by a numberof separate tracks conforms to an opposite side of the block of productwhether this is planar but non-parallel or whether it is of irregularshape.

BRIEF DESCRIPTION OF THE DRAWINGS

A particular example of a feeding device in accordance with thisinvention will now be described with reference to the accompanyingdrawings in which:

FIG. 1 is a simplified cut away side elevation of part of a slicingmachine;

FIG. 2 is a side elevation of part of the top feeding track assembly;

FIG. 3 is a front elevation of the top feeding track assembly with thetracks omitted;

FIG. 4 is an enlarged side elevation of part of the feeding track;

FIG. 5 is a perspective view of a pair of links of the feeding track;

FIG. 6 is a side elevation of .the lower feeding track;

FIG. 7 is a plan of the lower feeding track;

FIG. 8 is a cross section taken on the lines 8--8 shown in FIG. 7;

FIG. 9 is a rear elevation illustrating the drive to the upper and lowerfeeding tracks; and,

FIG. 10 is a diagram illustrating how the upper tracks conform to thesurface of the side of bacon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A slicing machine includes a blade 1 having a spiral cutting edge 2which, as the blade is rotated, moves along the plane of cut 3. Theslicing machine includes a feeding device comprising a top feeding trackassembly 4 and a lower feeding track assembly 5. The top feeding trackassembly 4 consists of four separate tracks 6, 7, 8 and 9 having aganged drive provided by a common axle 10 which drives driving sprocketwheels 11. Each top feeding track 6, 7, 8, 9 includes a frame 12 havingan idler sprocket wheel 13 at its downstream end and is pivoted aboutthe axle 10. The tracks 6, 7, 8, 9 are formed by a sprocket chain 14having a K-attachment 15 on its inner links to which stepped plates 16are connected. The axle 10 is rotatably journalled in a supporting yoke17 which is mounted on slidable guide pins 18 which are journalled inbearings 19 mounted in movable carriage 20.

A double acting pneumatic piston and cylinder assembly 21 is connectedand acts between the supporting yoke 17 and the movable carriage 20 and,in use, is arranged to urge the yoke 17 and with it the upstream ends ofthe tracks 6, 7, 8, 9 downwards. Four further double acting pneumaticcylinder assemblies 22 (which have been omitted from FIG. 3 for clarity)are connected and act between the movable carriage 20 and saddles 23attached to the frames 12. In use these urge the downstream ends of theframes 12 and hence the downstream ends of the tracks 6, 7, 8, 9downwards. A support 24 made of Delrin (Registered Trade Mark) isconnected to the frame 12 and provides support for the downstreamportion of the tracks 6, 7, 8, 9. A finger 25 is connected to one sideof each of the frames 12 and, in use, engages the surface of a block ofproduct immediately adjacent the plane of cut 3 of the blade 1.

The movable carriage 20 includes guide pins 25a which are journalled inbearings 26 connected to a main frame 27 of the slicing machine and ahand wheel 28 and lead screw assembly 29 is arranged to raise and lowerthe movable carriage 20 with respect to the main frame 27 to provide arough manual adjustment of the separation between the to and lowerfeeding track assemblies 4 and 5.

The lower feeding track assembly 5 comprises a pair of sprocket chains30 with their bearing pins extending on their inner faces which supportsquare sectioned rods 31. One end of each of the rods 31 is welded to anauxilliary link to prevent them rotating. Guides 32 support the sprocketchains 30 and hence support the product carried by them. The sprocketchains 30 extend between a pair of drive sprocket wheels 33 mounted on acommon axle 34 and roller sprocket wheels 35. An elongate guide 36extending transversely to the direction of movement of the feedingtracks 4 and 5 extends at a downstream end of the lower conveying trackassembly 5 to provide support for the product up to the plane of cut 3of the blade 1. The lower feeding track assembly 5 is mounted onbearings 37, 38 so that it can be moved bodily towards and away from theblade 1. This allows it to be withdrawn to enable access to be gained tothe top feeding track assembly 4 for maintainance and cleaning.

FIG. 9 illustrates the drive assembly and shows that the drive isconnected via an input shaft 39 and a releasable coupling 40 to the axle34 of the lower feeding track assembly 5 and via a sprocket wheel 41connected to the input shaft 39 and a reversing loop of sprocket chain(not shown) to a driven sprocket wheel 42. The driven sprocket wheel 42is connected by an extendible link 43, a universal joint 44 and then viaa second universal joint 45 to the driven axle 10 of the top feedingtrack assembly 4. The universal joints 44 and 45 and the extendible link43 accommodate the vertical upwards and downwards movement of the axle10.

FIG. 10 illustrates diagrammatically how the individual conveying tracks6, 7, 8 and 9 under the action of their pneumatic cylinder assemblies 22are forced downwards to conform to the surface of an irregularly shapedblock of meat such as a side of bacon 46.

I claim:
 1. A slicing machine including a rotatable blade and a feedingdevice for feeding blocks of product towards said blade, said feedingdevice comprising:opposed endless track assemblies having upstream anddownstream ends; drive means connected to said opposed endless trackassemblies and arranged to drive adjacent faces of said opposed endlesstrack assemblies in the same direction; a common support; one of saidopposed endless track assemblies being formed by a plurality of separatelongitudinally extending feeding tracks, said plurality of separatelongitudinally extending feeding tracks being arranged side-by-side andbeing pivotally connected to said common support, said drive meansproviding a ganged drive for all of said plurality of separatelongitudinally extending feeding tracks; biasing means operativelyconnected to said plurality of separate longitudinally extending feedingtracks and arranged to urge downstream ends of said separatelongitudinally extending feeding tracks independently towards the otheropposed endless track assembly whereby, in use, said separatelongitudinally extending feeding tracks pivot independently and hold ablock of product the thickness of which is non-uniform in a directiontransverse to said same direction in which said adjacent faces of saidopposed endless track assemblies are driven; mounting means slidablymounting said common support for movement in a direction parallel to aplane of rotation of said rotatably blade; and, pneumatic actuatorsoperatively connected to said common support and arranged to urge saidcommon support towards said other opposed endless track assembly andthereby, in use, accommodate differences in thickness between subsequentblocks of product without pivoting movement of said plurality oflongitudinally extending feeding tracks.
 2. A slicing machine accordingto claim 1, in which elongate guide fingers (25) are intercallatedbetween the separate longitudinally extending feeding tracks (6, 7, 8,9) and are arranged to engage and support the product immediatelyadjacent the blade (1) and so support the product right up to adownstream end of the feeding tracks.
 3. A slicing machine according toclaim 2, in which each finger is connected to a support for one of theseparate longitudinally extending feeding tracks (6, 7, 8, 9) and movestowards and away from said opposed endless track assembly (5) with arespective one of the separate longitudinally extending feeding tracks(6, 7, 8, 9).
 4. A slicing machine according to any of claims 2, 3, or1, in which the separate longitudinally extending feeding tracks (6, 7,8, 9) include a support (24) arranged towards said downstream endthereof to bear against the separate feeding tracks (6, 7, 8, 9) andurge them towards said opposed endless track assembly (5).
 5. A slicingmachine according to any of claims 2, 3, or 1, in which the separatefeeding tracks (6, 7, 8, 9) comprise sprocket chains (14) havingtransverse plates (16) attached to adjacent links.
 6. A slicing machineaccording to claim 5, in which the transverse plates (16) have a steppedsurface to engage the block of product (46).
 7. A slicing machineaccording to any of claims 2, 3, or 1, in which the biasing means are anumber of pneumatic actuators (22) arranged and acting between thesupport (20) and the downstream end of the separate feeding tracks (6,7, 8, 9).